The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The seat provided in transportation devices such as a vehicle includes a seat back for supporting the upper body of the passenger, a seat cushion for supporting the lower body such as the buttocks and thighs, and a headrest for supporting the back of the head, wherein at a junction of the seat back and the seat cushion, a reclining device is mounted, which allows the angle of the seat back to be adjusted relative to the seat cushion.
The reclining device is divided into a manual-type reclining device, in which the angle of the seat back is adjusted by the passenger manipulating a lever, and a power-type reclining device, which is automatically operated by the power of a motor through manipulating a switch, and all reclining devices, regardless of how they work, have strong coupling between components during the reclining operation to maintain passenger comfort and provide passenger safety.
In other words, the reclining device includes a component coupled with the seat back and a component coupled with the seat cushion and the two components exert a strong engagement force during the reclining operation. If the seat back has a weak engagement force, the angle of the seat back may be easily changed even with minor impact. In this case, the angle of the seat back is changed when an impact occurs, so that the passenger is injured.
As described above, in order for the reclining device to have a strong engagement force, it is necessary to maintain the locked state based on a strong elastic force so that the internal engagement is maintained well. To achieve this, the stronger elasticity a spring in the recliner has, the more stability the reclining device has.
However, conventionally, the spring of the recliner is placed inside and an elastic force for locking is applied to an input member, but the type and size of the spring is very limited since an inner space of the recliner is confined.